Indoor heat exchanger and air conditioning apparatus

ABSTRACT

An indoor heat exchanger in an indoor unit of an air conditioning apparatus, includes: flat tubes that are juxtaposed in a vertical direction and that each comprise a flow channel that allows refrigerant to pass through an inner portion thereof, and heat transfer fins joined to the flat tubes. The heat transfer fins each include: a first portion that extends continuously in the vertical direction; and second portions that are disposed between the flat tubes. The first portion and the second portions are continuous. 4.0≤DP/HT≤10.0 where HT is a height of each of the flat tubes and DP is a pitch of the flat tubes.

TECHNICAL FIELD

The present invention relates to an indoor heat exchanger and an airconditioning apparatus.

BACKGROUND

As an existing outdoor heat exchanger included in an outdoor unit of anair conditioning apparatus, for example, PTL 1 (Japanese UnexaminedPatent Application Publication No. 2016-041986) discloses an outdoorheat exchanger in which heat transfer fins are joined to a plurality offlat tubes.

When such a heat exchanger in which heat transfer fins are joined to aplurality of flat tubes is used in an indoor unit of an air conditioningapparatus, dew condensation water that is generated when the heatexchanger functions as an evaporator for refrigerant disperses into anindoor space.

SUMMARY

One or more embodiments of the present invention provide an indoor heatexchanger including a plurality of flat tubes capable of suppressingdispersion of dew condensation water, and an air conditioning apparatus.

An indoor heat exchanger according to a first aspect is an indoor heatexchanger used in an indoor unit of an air conditioning apparatus. Theindoor heat exchanger includes a plurality of flat tubes and a pluralityof heat transfer fins. The flat tubes each include a flow channel thatallows refrigerant to pass through an inner portion thereof. Theplurality of flat tubes are vertically juxtaposed (i.e., disposed in avertical direction). The plurality of heat transfer fins are joined tothe plurality of flat tubes. The heat transfer fins each include acontinuous portion. The continuous portion extends vertically (i.e.,extends in the vertical direction). The continuous portion of each heattransfer fin is a portion of the heat transfer fin and continuous withportions positioned between the flat tubes vertically juxtaposed. Theindoor heat exchanger satisfies the relation of 4.0≤DP/HT≤10.0. HTrepresents the height of each of the flat tubes. DP represents the pitchof the flat tubes vertically juxtaposed.

The indoor heat exchanger enables, even when the flow rate of theairflow supplied to the indoor heat exchanger is increased, suppressionof dispersion of dew condensation water that is generated when theindoor heat exchanger is used as an evaporator for refrigerant.

An indoor heat exchanger according to a second aspect is an indoor heatexchanger used in an indoor unit. The indoor unit constitutes an airconditioning apparatus in cooperation with an outdoor unit that includesan outdoor heat exchanger. The outdoor heat exchanger includes aplurality of flat tubes and a plurality of heat transfer fins. Theindoor heat exchanger also includes a plurality of flat tubes and aplurality of heat transfer fins. These flat tubes each include a flowchannel that allows refrigerant to pass through an inner portionthereof. The plurality of flat tubes are vertically juxtaposed. Theplurality of fins are joined to the plurality of flat tubes. The heattransfer fins each include a continuous portion. The continuous portionextends vertically. The continuous portion of each heat transfer fin isa portion of the heat transfer fin and continuous with portionspositioned between the flat tubes vertically juxtaposed. The value ofDP/HT of the indoor heat exchanger is smaller than the value of DP/HT ofthe outdoor heat exchanger. HT represents the height of each of the flattubes. DP represents the pitch of the flat tubes vertically juxtaposed.

The indoor heat exchanger enables suppression of dispersion of dewcondensation water that is generated when the indoor heat exchanger isused as an evaporator for refrigerant while suppressing frost formationthat occurs when the outdoor heat exchanger is used as an evaporator forrefrigerant.

An indoor heat exchanger according to a third aspect is the indoor heatexchanger according to the first aspect or the second aspect, in whichthe flat tubes each include a plurality of upstream-side flat tubesdisposed on the upstream side in an airflow direction, and a pluralityof downstream-side flat tubes disposed on the downstream side in theairflow direction from the upstream-side flat tubes.

The indoor heat exchanger enables suppression of dispersion of dewcondensation water from the downstream-side ends of the downstream-sideflat tubes in the airflow direction.

An indoor heat exchanger according to a fourth aspect is the indoor heatexchanger according to any one of the first aspect to the third aspect,in which the continuous portion is positioned on the leeward side of theflat tubes in the airflow direction.

The indoor heat exchanger enables suppression of dispersion of dewcondensation water from the downstream-side ends of the heat transferfins in the airflow direction by guiding the dew condensation water thathas been generated on the flat tubes to move downward along thecontinuous portions of the heat transfer fins positioned on thedownstream side in the airflow direction.

An indoor heat exchanger according to a fifth aspect is the indoor heatexchanger according to any one of the first aspect to the fourth aspect,in which the relation of 0.2≤WL/WF≤0.5 is satisfied. WF represents thelength of each of the heat transfer fins in the airflow direction. WLrepresents the length of the continuous portion in the airflowdirection.

The indoor heat exchanger enables suppression of dispersion of dewcondensation water by sufficiently ensuring the continuous portion whilesuppressing material costs of the heat transfer fins.

An indoor heat exchanger according to a sixth aspect is the indoor heatexchanger according to any one of the first aspect to the fifth aspect,in which the heat transfer fins each include a cut-and-raised portion.The longitudinal direction of the cut-and-raised portion is the up-downdirection (i.e., the vertical direction).

Due to the heat transfer fins each including the cut-and-raised portion,the indoor heat exchanger enables an improvement in heat transferperformance.

An indoor heat exchanger according to a seventh aspect is the indoorheat exchanger according to any one of the first aspect to the sixthaspect, in which the relation of 4.6≤DP/HT≤8.0 is satisfied.

The indoor heat exchanger more easily suppresses dispersion of dewcondensation water that is generated when the indoor heat exchanger isused as an evaporator for refrigerant.

An air conditioning apparatus according to an eighth aspect includes anindoor unit including the indoor heat exchanger according to any one ofthe first aspect to the seventh aspect, and an outdoor unit including anoutdoor heat exchanger.

The air conditioning apparatus easily suppresses dispersion of dewcondensation water that is generated when the indoor heat exchanger isused as an evaporator for refrigerant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of air conditioning apparatus.

FIG. 2 is a perspective view schematically illustrating the externalappearance of an outdoor unit.

FIG. 3 is a schematic plan view of an outdoor unit.

FIG. 4 is a perspective view schematically illustrating the externalappearance of an outdoor heat exchanger.

FIG. 5 is an illustration of a positional relation between outdoor finsand outdoor flat tubes.

FIG. 6 is a perspective view schematically illustrating the externalappearance of an indoor unit.

FIG. 7 is a schematic plan view of an indoor unit.

FIG. 8 is a schematic side view of the indoor unit along the A-A sectionof FIG. 7.

FIG. 9 is a perspective view schematically illustrating the externalappearance of an indoor heat exchanger.

FIG. 10 is a partially enlarged perspective view schematicallyillustrating the external appearance of the indoor heat exchanger.

FIG. 11 is an illustration of the positional relation between indoorfins and indoor flat tubes.

FIG. 12 is an illustration of a joined state between the indoor fins andthe indoor flat tubes.

FIG. 13 is an illustration of the positional relation between indoorfins and indoor flat tubes according to a modification A.

FIG. 14 is an illustration of a portion of a water-guiding rib includedin each of the indoor fins according to the modification A, along theB-B section of FIG. 13, the portion being in the vicinity of thedownstream side in an airflow direction.

DETAILED DESCRIPTION (1) Configuration of Air Conditioning Apparatus

FIG. 1 is a schematic diagram of an air conditioning apparatus 1.

The air conditioning apparatus 1 is an apparatus capable of cooling andheating a room of a building or the like by performing a vaporcompression refrigeration cycle.

The air conditioning apparatus 1 includes, mainly, an outdoor unit 2, anindoor unit 3, and a liquid-refrigerant connection pipe 4 and agas-refrigerant connection pipe 5 that are refrigerant paths connectingthe outdoor unit 2 and the indoor unit 3 to each other. A vaporcompression refrigerant circuit 6 of the air conditioning apparatus 1 isconstituted by the outdoor unit 2 and the indoor unit 3 being connectedto each other via the refrigerant connection pipes 4 and 5. Therefrigerant connection pipes 4 and 5 are refrigerant pipes that areconstructed locally during installation of the air conditioningapparatus 1 in an installation location in a building or the like. Inone or more embodiments, the refrigerant circuit 6 is packed with R32 asa working refrigerant; however, the working refrigerant is not limitedthereto.

(2) Outdoor Unit (2-1) General Configuration of Outdoor Unit

The outdoor unit 2 is installed outside (for example, on the rooftop ofa building or in the vicinity of a wall surface of a building) andconstitutes a portion of the refrigerant circuit 6. The outdoor unit 2includes, mainly, an accumulator 7, a compressor 8, a four-way switchingvalve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 asan expansion mechanism, a liquid-side shutoff valve 13, a gas-sideshutoff valve 14, an outdoor fan 15, and a casing 40.

The accumulator 7 is a container for supplying a gas refrigerant to thecompressor and is disposed on the suction side of the compressor 8.

The compressor 8 sucks and compresses a low-pressure gas refrigerant anddischarges a high-pressure gas refrigerant.

The outdoor heat exchanger 11 is a heat exchanger that functions duringa cooling operation as a radiator for refrigerant that is dischargedfrom the compressor 8 and that functions during a heating operation asan evaporator for refrigerant that is sent from an indoor heat exchanger51. The outdoor heat exchanger 11 is connected at the liquid sidethereof to the outdoor expansion valve 12 and connected at the gas sidethereof to the four-way switching valve 10.

The outdoor expansion valve 12 is an electric expansion valve capableof, during a cooling operation, decompressing refrigerant whose heat isradiated in the outdoor heat exchanger 11 before sending the refrigerantto the indoor heat exchanger 51 and, during a heating operation,decompressing refrigerant whose heat is radiated in the indoor heatexchanger 51 before sending the refrigerant to the outdoor heatexchanger 11.

One end of the liquid-refrigerant connection pipe 4 is connected to theliquid-side shutoff valve 13 of the outdoor unit 2. One end of thegas-refrigerant connection pipe 5 is connected to the gas-side shutoffvalve 14 of the outdoor unit 2.

Devices of the outdoor unit 2 and the valves are connected to each otherby refrigerant pipes 16 to 22.

The four-way switching valve 10 switches between a connection state fora cooling operation and a connection state for a heating operation,which are to be described later, by switching between a state (see thesolid lines in the four-way switching valve 10 in FIG. 1) in which thedischarge side of the compressor 8 is connected to the side of theoutdoor heat exchanger 11 and in which the suction side of thecompressor 8 is connected to the side of the gas-side shutoff valve 14and a state (see the dashed lines in the four-way switching valve 10 inFIG. 1) in which the discharge side of the compressor 8 is connected tothe side of the gas-side shutoff valve 14 and in which the suction sideof the compressor 8 is connected to the side of the outdoor heatexchanger 11.

The outdoor fan 15 is disposed in an inner portion of the outdoor unit 2and, after taking outdoor air therein and supplying the outdoor air tothe outdoor heat exchanger 11, forms an airflow (indicated by arrows inFIG. 3) that is discharged to the outside of the unit. As above, theoutdoor air supplied by the outdoor fan 15 is used as a cooling sourceor a heating source in a heat exchange with the refrigerant of theoutdoor heat exchanger 11.

As illustrated in the perspective view schematically illustrating theexternal appearance of the outdoor unit 2 in FIG. 2 and in the schematicplan view of the outdoor unit 2 in FIG. 3, the casing 40 includes,mainly, a bottom frame 40 a, a top panel 40 b, a left front panel 40 c,a right front panel 40 d, and a right-side panel 40 e. The bottom frame40 a is a laterally elongated substantially rectangular plate-shapedmember that constitutes the bottom surface portion of the casing 40. Thebottom frame 40 a is set on a local installation surface via fixed legs41 fixed to the lower surface of the bottom frame 40 a. The top panel 40b is a laterally elongated substantially rectangular plate-shaped memberthat constitutes the top surface portion of the casing 40. The leftfront panel 40 c is a plate-shaped member that constitutes, mainly, theleft front surface portion and the left-side surface portion of thecasing 40 and includes two blow-out ports for blowing out, to the frontsurface side, the air that has been taken into the casing 40 from theback surface side and the left-side surface side by the outdoor fan 15.The blow-out ports are vertically juxtaposed. A fan grille 42 isdisposed at each of the blow-out ports. The right front panel 40 d is aplate-shaped member that constitutes, mainly, the right front surfaceportion and the front portion of the right side surface of the casing40. The right-side panel 40 e is a plate-shaped member that constitutes,mainly, the rear portion of the right side surface and the right backsurface portion of the casing 40.

In the casing 40, a partition plate 43 that partitions a fan chamber inwhich the outdoor fan 15 and the like are disposed and a machine chamberin which the compressor 8 and the like are disposed from each other isdisposed.

(2-2) Overall Structure of Outdoor Heat Exchanger

FIG. 4 is a perspective view schematically illustrating the externalappearance of the outdoor heat exchanger 11.

The outdoor heat exchanger 11 includes, mainly, a gas-side flow divider23, a liquid-side flow divider 24, a plurality of inflow-side returningmembers 25, a plurality of opposite-inflow-side returning members 26, aplurality of outdoor flat tubes 90, and a plurality of outdoor fins 91.All of these components that constitute the outdoor heat exchanger 11are formed of aluminum or an aluminum alloy and joined to each other bybrazing or the like.

The plurality of outdoor flat tubes 90 are vertically juxtaposed.

The plurality of outdoor fins 91 are disposed side by side in a platethickness direction thereof so as to extend along the outdoor flat tubes90 and are fixed to the plurality of the outdoor flat tubes 90.

The gas-side flow divider 23 is connected to the refrigerant pipe 19and, of the plurality of the outdoor flat tubes 90, the outdoor flattubes 90 disposed in an upper portion. When the outdoor heat exchanger11 functions as a radiator for the refrigerant, the flow of therefrigerant that has flowed from the refrigerant pipe 19 into theoutdoor heat exchanger 11 is divided into flows at a plurality of heightpositions and sent to, of the plurality of outdoor flat tubes 90, theoutdoor flat tubes 90 disposed in the upper portion.

The liquid-side flow divider 24 is connected to the refrigerant pipe 20and, of the plurality of outdoor flat tubes 90, the outdoor flat tubes90 disposed in a lower portion. When the outdoor heat exchanger 11functions as a radiator for the refrigerant, the flows of therefrigerant that have flowed from, of the plurality of outdoor flattubes 90, the outdoor flat tubes 90 disposed in the lower portion aremerged together and caused to flow to the outside of the outdoor heatexchanger 11 through the refrigerant pipe 20.

The plurality of inflow-side returning members 25 are disposed betweenthe gas-side flow divider 23 and the liquid-side flow divider 24 andconnect ends of the outdoor flat tubes 90 disposed at mutually differentheight positions to each other.

The opposite-inflow-side returning members 26 are disposed at an end ofthe outdoor heat exchanger 11 on a side opposite to a side where thegas-side flow divider 23, the liquid-side flow divider 24, and theplurality of inflow-side returning members 25 are disposed. Theopposite-inflow-side returning members 26 connect ends of the outdoorflat tubes 90 disposed at mutually different height positions to eachother.

As above, by including the plurality of inflow-side returning members 25and the opposite-inflow-side returning members 26, the outdoor heatexchanger 11 enables the refrigerant to flow while returning at bothends of the outdoor heat exchanger 11.

(2-3) Outdoor Flat Tube

FIG. 5 illustrates a positional relation between the outdoor fins 91 andthe outdoor flat tubes 90 viewed, in a state of being sectioned along asection perpendicular to a direction in which flow channels 90 c ininner portions of the outdoor flat tubes 90 extend, in the direction inwhich the flow channels 90 c extend.

The outdoor flat tubes 90 each include an upper-side flat surface 90 afacing vertically upward and constituting the upper surface, alower-side flat surface 90 b facing vertically downward and constitutingthe lower surface, and a large number of the flow channels 90 c that aresmall and in which refrigerant flows. The plurality of flow channels 90c included in the outdoor flat tubes 90 are disposed side by side in anairflow direction (indicated by arrows in FIG. 5; the longitudinaldirection of the outdoor flat tubes 90 in a sectional view of the flowchannels 90 c). The plurality of outdoor flat tubes 90 that are used areidentical to each other in terms of a height HT in an up-down direction.The height HT denotes a width between the upper-side flat surface 90 aand the lower-side flat surface 90 b of each outdoor flat tube 90 in theheight direction. The plurality of outdoor flat tubes 90 are arranged inthe up-down direction at a predetermined pitch (stage pitch DP). Thestage pitch DP is an interval between the upper-side flat surfaces 90 aof the outdoor flat tubes 90.

The outdoor heat exchanger 11 according to one or more embodiments isconfigured such that downstream-side ends of the plurality of outdoorflat tubes 90 in the airflow direction are positioned on the downstreamside from downstream-side ends of the outdoor fins 91 in the airflowdirection. Consequently, the leeward-side ends of the outdoor fins 91are suppressed from being damaged or broken during manufacture ortransport of the outdoor heat exchanger 11.

(2-4) Outdoor Fin

The outdoor fins 91 are plate-shaped members extending in the airflowdirection and in the up-down direction. A plurality of the outdoor fins91 are disposed in the plate thickness direction thereof atpredetermined intervals and fixed to the outdoor flat tubes 90.

The outdoor fins 91 each include a plurality of insertion portions 92,an outdoor continuous portion 97 a, a plurality of leeward portions 97b, a waffle portion 93, windward-side fin tabs 94 a, leeward-side fintabs 94 b, outdoor slits 95, windward-side ribs 96 a, leeward-side ribs96 b, and the like. The thickness of each outdoor fin 91 at a flatportion in the plate thickness direction is, for example, 0.05 mm ormore and 0.15 mm or less.

Each of the insertion portions 92 is formed by being horizontally cutfrom the leeward-side edge of the outdoor fin 91 toward the windwardside to a portion before the windward-side edge thereof. The pluralityof insertion portions 92 are disposed side by side in the up-downdirection. The insertion portions 92 constitute a fin collar that isformed by burring or the like. The shape of each of the insertionportions 92 is substantially in coincident with the outer shape of thesection of each outdoor flat tube 90. The outdoor flat tubes 90 arefixed to the outdoor fins 91 at the insertion portions 92 by brazing ina state of being inserted into the insertion portions 92.

The outdoor continuous portion 97 a is, of each outdoor fin 91, aportion that is continuous in the up-down direction on the furtherwindward side from the windward-side ends of the outdoor flat tubes 90.From the point of view of ensuring frost proof performance, a distancein the airflow direction from the windward ends of the outdoor flattubes 90 to the windward end of the outdoor continuous portion 97 a ofeach outdoor fin 91 may be 4 mm or more.

The plurality of leeward portions 97 b extend from different heightpositions in the outdoor continuous portion 97 a toward the downstreamside in the airflow direction. Each leeward portion 97 b is surroundedin the up-down direction by the insertion portions 92 adjacent to eachother.

The waffle portion 93 is formed, in each outdoor fin 91, in the vicinityof the center in the airflow direction and configured to include a bumppart and a non-bump part in the plate thickness direction.

The windward-side fin tabs 94 a and the leeward-side fin tabs 94 b aredisposed in the vicinity of the windward-side ends and in the vicinityof the leeward-side ends, respectively, to restrict the interval betweenthe outdoor fins 91.

Each outdoor slit 95 is a portion that is configured by being cut andraised in the plate thickness direction from a flat part to improve theheat transfer performance of the outdoor fins 91 and is formed on thedownstream side of the waffle portion 93 in the airflow direction. Eachoutdoor slit 95 has a longitudinal direction in the up-down direction(the arrangement direction of the outdoor flat tubes 90). A plurality(two shown in FIG. 5) of the outdoor slits 95 are disposed side by sidein the airflow direction. These outdoor slits 95 are cut and raised fromthe flat part on the same side in the plate thickness direction, therebyhaving openings on the upstream side and the downstream side in theairflow direction, respectively.

The windward-side ribs 96 a are disposed above and below thewindward-side fin tabs 94 a to extend in the airflow direction betweenmutually vertically adjacent outdoor flat tubes 90. The leeward-sideribs 96 b continue from the leeward-side ends of the windward-side ribs96 a and extend further on the leeward side.

(3) Indoor Unit (3-1) General Configuration of Indoor Unit

FIG. 6 is a perspective view of the external appearance of the indoorunit 3. FIG. 7 is a schematic plan view of the indoor unit 3 with thetop panel thereof removed. FIG. 8 is a schematic side sectional view ofthe indoor unit 3 along a section indicated by A-A in FIG. 7.

In one or more embodiments, the indoor unit 3 is an indoor unit of atype that is installed on a ceiling of a room or the like that is anair-conditioning target space by being embedded in an opening of theceiling. The indoor unit 3 constitutes a portion of the refrigerantcircuit 6. The indoor unit 3 includes, mainly, the indoor heat exchanger51, an indoor fan 52, a casing 30, a flap 39, a bell mouth 33, and adrain pan 32.

The indoor heat exchanger 51 is a heat exchanger that functions, duringa cooling operation, as an evaporator for the refrigerant sent from theindoor heat exchanger 51 and functions, during a heating operation, as aradiator for the refrigerant discharged from the compressor 8. Theindoor heat exchanger 51 is connected at the liquid side thereof to theindoor-side end of the liquid-refrigerant connection pipe 4 andconnected at the gas side thereof to the indoor-side end of thegas-refrigerant connection pipe 5.

The indoor fan 52 is a centrifugal fan disposed in an inner portion of acasing body 31 of the indoor unit 3. The indoor fan 52 takes indoor airthrough an intake port 36 of a decorative panel 35 into the casing 30and, after causing the air to pass through the indoor heat exchanger 51,forms an airflow (indicated by arrows in FIG. 8) that blows out to theoutside of the casing 30 through a blow-out port 37 of the decorativepanel 35. The indoor air thus supplied by the indoor fan 52 exchangesheat with the refrigerant of the indoor heat exchanger 51, and thetemperature of the indoor air is thereby controlled.

The casing 30 includes, mainly, the casing body 31 and the decorativepanel 35.

The casing body 31 is disposed to be inserted into an opening formed ina ceiling U of an air-conditioned room. In plan view, the casing body 31is a substantially octagonal box-shaped body having long sides and shortsides alternately formed. The casing body 31 has an open lower surface.The casing body 31 includes a top panel and a plurality of side platesextending downward from the peripheral portion of the top panel.

The decorative panel 35 is disposed to be fitted into the opening of theceiling U and extends further on the outer side in plan view than thetop panel and the side plates of the casing body 31. The decorativepanel 35 is mounted below the casing body 31 from the indoor side. Thedecorative panel 35 includes an inner frame 35 a and an outer frame 35b. On the inner side of the inner frame 35 a, the intake port 36 openingdownward and having a substantially quadrangular shape is formed. Afilter 34 for removing dust in air that has been taken in through theintake port 36 is disposed above the intake port 36. In a part that ison the inner side of the outer frame 35 b and on the outer side of theinner frame 35 a, the blow-out port 37 and a corner blow-out port 38that open to be directed obliquely downward from the lower portion ofthe part are formed. The blow-out port 37 includes, in locationscorresponding to the sides of the substantially quadrangular shape ofthe decorative panel 35 in plan view, a first blow-out port 37 a, asecond blow-out port 37 b, a third blow-out port 37 c, and a fourthblow-out port 37 d. The corner blow-out port 38 includes, in locationscorresponding to the four corners of the substantially quadrangularshape of the decorative panel 35 in plan view, a first corner blow-outport 38 a, a second corner blow-out port 38 b, a third corner blow-outport 38 c, and a fourth corner blow-out port 38 d.

The flap 39 is a member capable of changing a direction of an airflowthat passes through the blow-out port 37. The flap 39 includes a firstflap 39 a disposed in the first blow-out port 37 a, a second flap 39 bdisposed in the second blow-out port 37 b, a third flap 39 c disposed inthe third blow-out port 37 c, and a fourth flap 39 d disposed in thefourth blow-out port 37 d. Each of the flaps 39 a to 39 d is rotatablysupported in a predetermined location in the casing 30.

The drain pan 32 is disposed on the lower side of the indoor heatexchanger 51 and receives drain water that is generated as a result ofmoisture in air condensing in the indoor heat exchanger 51. The drainpan 32 is mounted in a lower portion of the casing body 31. The drainpan 32 includes a cylindrical space extending in the up-down directionon the inner side of the indoor heat exchanger 51 in plan view. The bellmouth 33 is disposed in an inner lower portion of the space. The bellmouth 33 guides the air that is taken in through the intake port 36 tothe indoor fan 52. The drain pan 32 includes a plurality of blow-outflow channels 47 a to 47 d and corner blow-out flow channels 48 a to 48c that extend in the up-down direction on the outer side of the indoorheat exchanger 51 in plan view. The blow-out flow channels 47 a to 47 dinclude a first blow-out flow channel 47 a in communication at the lowerend thereof with the first blow-out port 37 a, a second blow-out flowchannel 47 b in communication at the lower end thereof with the secondblow-out port 37 b, a third blow-out flow channel 47 c in communicationat the lower end thereof with the third blow-out port 37 c, and a fourthblow-out flow channel 47 d in communication at the lower end thereofwith the fourth blow-out port 37 d. The corner blow-out flow channels 48a to 48 c include a first corner blow-out flow channel 48 a incommunication at the lower end thereof with the first corner blow-outport 38 a, a second corner blow-out flow channel 48 b in communicationat the lower end thereof with the second corner blow-out port 38 b, anda third corner blow-out flow channel 48 c in communication at the lowerend thereof with the third corner blow-out port 38 c.

(3-2) Overall Structure of Indoor Heat Exchanger

FIG. 9 is a perspective view schematically illustrating the externalappearance of the indoor heat exchanger 51. FIG. 10 is a partiallyenlarged perspective view of the external appearance of the indoor heatexchanger 51 on the windward side of a plurality of indoor fins 60.

The indoor heat exchanger 51 is disposed, in an inner portion of thecasing body 31, at a height position identical to the height position ofthe indoor fan 52 in a state of being bent to surround the periphery ofthe indoor fan 52. The indoor heat exchanger 51 includes, mainly, aliquid-side header 81, a gas-side header 71, a return header 59, aplurality of indoor flat tubes 55, and a plurality of the indoor fins60. All of these components that constitute the indoor heat exchanger 51are formed of aluminum or an aluminum alloy and joined to each other bybrazing or the like.

The indoor heat exchanger 51 includes a windward heat exchanging section70 (inner part in plan view) that constitutes the windward side thereofin the airflow direction, and a leeward heat exchanging section 80(outer part in plan view) that constitutes the leeward side thereof inthe airflow direction.

The liquid-side header 81 constitutes, of the indoor heat exchanger 51,one end of the leeward heat exchanging section 80 in plan view and is acylindrical member extending in the up-down direction. An indoor-sideend of the liquid-refrigerant connection pipe 4 is connected to theliquid-side header 81. A plurality of the indoor flat tubes 55 thatconstitute, of the indoor heat exchanger 51, the leeward heat exchangingsection 80 are connected to the liquid-side header 81 so as to bedisposed side by side vertically.

The gas-side header 71 constitutes, of the indoor heat exchanger 51, oneend of the windward heat exchanging section 70 in plan view and is acylindrical member extending in the up-down direction. The indoor-sideend of the gas-refrigerant connection pipe 5 is connected to thegas-side header 71. A plurality of the indoor flat tubes 55 thatconstitute, of the indoor heat exchanger 51, the windward heatexchanging section 70 are connected to the gas-side header 71 so as tobe disposed side by side vertically.

The return header 59 constitutes, of the indoor heat exchanger 51, anend on a side opposite to the side where the liquid-side header 81 andthe gas-side header 71 are disposed in plan view and includes aplurality of return spaces disposed side by side in an inner portionthereof in the up-down direction. The indoor flat tubes 55 constitutingthe windward heat exchanging section 70 and the indoor flat tubes 55constituting the leeward heat exchanging section 80 are connected to thereturn spaces disposed at height positions identical to respectiveheight positions of the indoor flat tubes 55. Consequently, the returnheader 59 enables, while suppressing the refrigerants that have flowedthrough the indoor flat tubes 55 at different height positions frommixing together, the refrigerants that have flowed through the indoorflat tubes 55 at respective height positions to return to be sent to theindoor flat tubes 55 at height positions identical to the heightpositions thereof on the windward side (when the indoor heat exchanger51 function as the evaporator for the refrigerant) or on the leewardside (when the indoor heat exchanger 51 functions as the radiator forthe refrigerant).

The plurality of indoor flat tubes 55 include indoor flat tubes thatconstitute the windward heat exchanging section 70 and indoor flat tubesthat constitute the leeward heat exchanging section 80. In other words,the plurality of indoor flat tubes 55 include indoor flat tubes that arejuxtaposed in the up-down direction in the windward heat exchangingsection 70 of the indoor heat exchanger 51 and indoor flat tubes thatare juxtaposed in the up-down direction in the leeward heat exchangingsection 80 of the indoor heat exchanger 51. The plurality of indoor flattubes 55 constituting the windward heat exchanging section 70 are eachconnected at one end thereof to the gas-side header 71 and connected atthe other end thereof to the windward-side part of the return header 59.The plurality of the indoor flat tubes 55 constituting the leeward heatexchanging section 80 are each connected at one end thereof to theliquid-side header 81 and connected at the other end thereof to theleeward-side part of the return header 59.

Similarly, the plurality of indoor fins 60 include indoor fins thatconstitute the windward heat exchanging section 70 and indoor fins thatconstitute the leeward heat exchanging section 80. In other words, theplurality of indoor fins 60 include indoor fins that are fixed to theindoor flat tubes 55 that constitute the windward heat exchangingsection 70 of the indoor heat exchanger 51, and indoor fins that arefixed to the indoor flat tubes 55 that constitute the leeward heatexchanging section 80 of the indoor heat exchanger 51. The indoor fins60 are disposed side by side in the plate thickness direction of theindoor fins 60 such that each indoor fin 60 extends along the indoorflat tubes 55.

(3-3) Indoor Flat Tube

FIG. 11 illustrates a positional relation between the indoor fins 60 andthe indoor flat tubes 55 viewed, in a state of being sectioned along asection perpendicular to a direction in which flow channels 55 c in theinner portions of the indoor flat tubes 55 extend, in the direction inwhich the flow channels 55 c extend.

The indoor flat tubes 55 each include an upper-side flat surface 55 afacing vertically upward and constituting the upper surface, alower-side flat surface 55 b facing vertically downward and constitutingthe lower surface, and a large number of the flow channels 55 c that aresmall and in which refrigerant flows. The plurality of flow channels 55c included in the indoor flat tubes 55 are disposed side by side in anairflow direction (indicated by arrows in FIG. 11; the longitudinaldirection of the indoor flat tubes 55 in a sectional view of the flowchannels 55 c). The plurality of indoor flat tubes 55 that are identicalto each other in terms of the height HT in the up-down direction areused. The height HT denotes a width between the upper-side flat surface55 a and the lower-side flat surfaces 55 b of the indoor flat tubes 55in the height direction. The height HT may be 1.2 mm or more and 2.5 mmor less. The plurality of indoor flat tubes 55 are arranged at apredetermined pitch (stage pitch DP) in the up-down direction similarlyboth in the windward heat exchanging section 70 and in the leeward heatexchanging section 80. The stage pitch DP is an interval between theupper-side flat surfaces 55 a of the indoor flat tubes 55 and may be 8.0mm or more and 15.0 mm or less. The indoor heat exchanger 51 satisfiesthe relation of 4.0≤DP/HT≤10.0. The lower limit of DP/HT of the indoorheat exchanger 51 may be 4.6 or more. The upper limit of DP/HT of theindoor heat exchanger 51 may be 8.0 or less. The indoor heat exchanger51 may satisfy the relation of 4.6≤DP/HT≤8.0.

The air conditioning apparatus 1 according to one or more embodimentssatisfies a relation in which the value of DP/HT of the indoor heatexchanger 51 is smaller than the value of DP/HT of the aforementionedoutdoor heat exchanger 11.

In one or more embodiments, the indoor flat tubes 55 constituting thewindward heat exchanging section 70 and the indoor flat tubes 55constituting the leeward heat exchanging section 80 are disposed to besuperposed on each other at respective height positions when viewed inthe airflow direction.

In the indoor heat exchanger 51 according to one or more embodiments,the upstream-side ends of the plurality of indoor flat tubes 55 in theairflow direction and the upstream-side ends of the indoor fins 60 inthe airflow direction are disposed at substantially identical positionsin the airflow direction.

(3-4) Indoor Fin

The indoor fins 60 are plate-shaped members extending in the airflowdirection and the up-down direction. A plurality of the indoor fins 60are disposed in the plate thickness direction thereof at predeterminedintervals and fixed to the indoor flat tubes 55. In one or moreembodiments, the indoor fins 60 constituting the windward heatexchanging section 70 and the indoor fins 60 constituting the leewardheat exchanging section 80 are disposed to be substantially superposedon each other when viewed in the airflow direction. The leeward-sideends of the indoor fins 60 constituting the windward heat exchangingsection 70 and the windward-side ends of the indoor fins 60 constitutingthe leeward heat exchanging section 80 are disposed in contact with eachother at least at a portion thereof.

Each of the indoor fins 60 constituting the windward heat exchangingsection 70 and each of the indoor fins 60 constituting the leeward heatexchanging section 80 both similarly include a major surface 61, aplurality of fin collar portions 65 a, an indoor continuous portion 64,a plurality of windward portions 65, main slits 62, continuous-locationslits 63, and the like. The thickness of the flat major surface 61 ofeach of the indoor fins 60 in the plate thickness direction is, forexample, 0.05 mm or more and 0.15 mm or less. The pitch (the intervalbetween the surfaces of mutually adjacent indoor fins 60 on the sameside) of the plurality of indoor fins 60 in the plate thicknessdirection may be 1.0 mm or more and 1.6 mm or less.

The major surface 61 constitutes, of the indoor fins 60, a flat part inwhich the fin collar portions 65 a, the main slits 62, and thecontinuous-location slits 63 are not disposed.

The fin collar portions 65 a are formed to extend horizontally from thewindward-side edges of the indoor fins 60 toward the leeward side to aportion before the leeward-side edge. The plurality of fin collarportions 65 a are disposed side by side in the up-down direction. Thefin collar portions 65 a are formed by burring or the like. The contourshape of each fin collar portion 65 a is substantially in coincidentwith the outer shape of the section of each indoor flat tube 55. Theindoor flat tubes 55 are fixed to the indoor fins 60 at the fin collarportions 65 a by brazing in a state of being inserted into the fincollar portions 65 a. FIG. 12 is an illustration of a joined statebetween the indoor fins 60 and the indoor flat tubes 55 in a section ofthe flow channels 55 c of the indoor flat tubes 55 taken in refrigerantpassing direction along a face including a vertical direction. Asillustrated in FIG. 12, the fin collar portions 65 a are configured bybeing raised with respect to the major surfaces 61 in the platethickness direction of the major surfaces 61 on a side opposite the sidewhere the main slits 62 are cut and raised. On a side opposite the sideof the major surfaces 61 of the fin collar portions 65 a, positioningportions 65 x that are bent to extend in a direction away from theupper-side flat surfaces 55 a (or the lower-side flat surfaces 55 b) ofthe indoor flat tubes 55 corresponding thereto are disposed. Thepositioning portions 65 x are in surface contact with the major surfaces61 of the indoor fins 60 adjacent thereto, thereby regulating theinterval between the indoor fins 60 in the plate thickness direction. Asillustrated in FIG. 12, the fin collar portions 65 a are joined bybrazing with brazing materials 58 interposed between the fin collarportions 65 a and the upper-side flat surfaces 55 a (or the lower-sideflat surfaces 55 b) of the indoor flat tubes 55. A distance DS between aportion where raising of the fin collar portions 65 a with respect tothe major surfaces 61 starts and a portion where raising of the mainslits 62 starts, as illustrated in FIG. 12, on the side of thelower-side flat surfaces 55 b of the indoor flat tubes 55 may be 1 mm orless but is not limited thereto. Dew condensation water on thelower-side flat surfaces 55 b of the indoor flat tubes 55 is guided tomove downward via the portion where the raising of the main slits 62starts and drained. Therefore, setting the distance DS to a shortdistance of 1 mm or less enables the dew condensation water to besuppressed from continuing to remain on the lower-side flat surfaces 55b of the indoor flat tubes 55.

The indoor continuous portion 64 is, of each indoor fin 60, a portioncontinuous in the up-down direction on the further leeward side from theleeward-side ends of the indoor flat tubes 55. The relation between awidth WL of the indoor continuous portion 64 of each indoor fin 60 inthe airflow direction and a width WF of each indoor fin 60 in theairflow direction may satisfy the relation of 0.2≤WL/WF≤0.5.

The plurality of windward portions 65 extend from different heightpositions in the indoor continuous portion 64 toward the upstream sidein the airflow direction. Each of the windward portions 65 is surroundedin the up-down direction by the fin collar portions 65 a adjacent toeach other. The length of each windward portion 65 in the up-downdirection is defined by DP—HT.

The main slits 62 are portions that are configured by being cut andraised in the plate thickness direction from the flat major surfaces 61to improve the heat transfer performance of the indoor fins 60. The mainslits 62 are formed in the windward portions 65 of the indoor fins 60. Aplurality (four shown in FIG. 11) of the main slits 62 are formed sideby side in the airflow direction.

The continuous-location slits 63 are also portions that are configuredby being cut and raised in the plate thickness direction from the flatmajor surfaces 61 to improve the heat transfer performance of the indoorfins 60. The continuous-location slits 63 are formed at a plurality ofheight positions in the indoor continuous portions 64 of the indoor fins60. The continuous-location slits 63 are disposed so as to eachcorrespond to the downstream side in the airflow direction of the mainslits 62 disposed at respective height positions. Thecontinuous-location slits 63 are formed such that the longitudinaldirection thereof is the up-down direction. The continuous-locationslits 63 are each elongated in the up-down direction such that the upperend thereof extends to a position higher than the upper ends of the mainslits 62 corresponding thereto and such that the lower end thereofextends to a position lower than the lower ends of the main slits 62corresponding thereto.

The main slits 62 and the continuous-location slits 63 are cut andraised from the flat major surfaces 61 on the same side in the platethickness direction, thereby having openings on the upstream side andthe downstream side in the airflow direction, respectively.

(4) Operation of Air Conditioning Apparatus

Next, with reference to FIG. 1, the operation of the air conditioningapparatus 1 will be described. The air conditioning apparatus 1 performsa cooling operation in which refrigerant flows through the compressor 8,the outdoor heat exchanger 11, the outdoor expansion valve 12, and theindoor heat exchanger 51 in this order and a heating operation in whichthe refrigerant flows through the compressor 8, the indoor heatexchanger 51, the outdoor expansion valve 12, and the outdoor heatexchanger 11 in this order.

(4-1) Cooling Operation

During a cooling operation, the connection state of the four-wayswitching valve 10 is switched to cause the outdoor heat exchanger 11 tofunction as the radiator for the refrigerant and the indoor heatexchanger 51 to function as the evaporator for the refrigerant (see thesolid lines in FIG. 1). In the refrigerant circuit 6, a low-pressure gasrefrigerant of the refrigeration cycle is sucked by the compressor 8 anddischarged after being compressed to a high pressure of therefrigeration cycle. The high-pressure gas refrigerant discharged fromthe compressor 8 is sent to the outdoor heat exchanger 11 through thefour-way switching valve 10. The high-pressure gas refrigerant sent tothe outdoor heat exchanger 11 radiates heat by, in the outdoor heatexchanger 11 that functions as the radiator for the refrigerant,exchanging the heat with outdoor air supplied as a cooling source by theoutdoor fan 15, thereby becoming a high-pressure liquid refrigerant. Thehigh-pressure liquid refrigerant is decompressed to a low pressure ofthe refrigeration cycle when passing through the outdoor expansion valve12, thereby becoming refrigerant in a gas-liquid two-phase state. Therefrigerant in the gas-liquid two-phase state is sent to the indoor unit3 through the liquid-side shutoff valve 13 and the liquid-refrigerantconnection pipe 4.

The low-pressure refrigerant in the gas-liquid two-phase stateevaporates by, in the indoor heat exchanger 51, exchanging heat withindoor air supplied as a heating source by the indoor fan 52 during acooling operation. Consequently, the air that passes through the indoorheat exchanger 51 is cooled, and cooling of the inside of a room isperformed. In this case, the moisture contained in the air that passesthrough the indoor heat exchanger 51 condenses and thereby generates dewcondensation water on the surface of the indoor heat exchanger 51. Thelow-pressure gas refrigerant that has evaporated in the indoor heatexchanger 51 is sent to the outdoor unit 2 through the gas-refrigerantconnection pipe 5.

The low-pressure gas refrigerant sent to the outdoor unit 2 is suckedagain by the compressor 8 through the gas-side shutoff valve 14,four-way switching valve 10, and an accumulator 7. During a coolingoperation, the refrigerant circulates in the refrigerant circuit 6 asdescribed above.

(4-2) Heating Operation

During a heating operation, the connection state of the four-wayswitching valve 10 is switched to cause the outdoor heat exchanger 11 tofunction as the evaporator for the refrigerant and the indoor heatexchanger 51 to function as the radiator for the refrigerant (see thedashed lines of FIG. 1). In the refrigerant circuit 6, a low-pressuregas refrigerant of the refrigeration cycle is sucked by the compressor 8and discharged after being compressed to a high pressure of therefrigeration cycle. The high-pressure gas refrigerant discharged fromthe compressor 8 is sent to the indoor unit 3 through the four-wayswitching valve 10, the gas-side shutoff valve 14, and thegas-refrigerant connection pipe 5.

The high-pressure gas refrigerant radiates heat by, in the indoor heatexchanger 51, exchanging the heat with indoor air supplied as a coolingsource by the indoor fan 52 and becomes a high-pressure liquidrefrigerant. Consequently, the air that passes through the indoor heatexchanger 51 is heated, and heating of the inside of a room isperformed. The high-pressure liquid refrigerant that has radiated heatin the indoor heat exchanger 51 is sent to the outdoor unit 2 throughthe liquid-refrigerant connection pipe 4.

The high-pressure liquid refrigerant sent to the outdoor unit 2 isdecompressed to a low pressure of the refrigeration cycle in the outdoorexpansion valve 12 through the liquid-side shutoff valve 13 and becomesa low-pressure refrigerant in a gas-liquid two-phase state. Thelow-pressure refrigerant in the gas-liquid two-phase state decompressedin the outdoor expansion valve 12 evaporates by, in the outdoor heatexchanger 11 that functions as the evaporator for the refrigerant,exchanging heat with outdoor air supplied as a heating source by theoutdoor fan 15, thereby becoming a low-pressure gas refrigerant. Thelow-pressure gas refrigerant is sucked again by the compressor 8 throughthe four-way switching valve 10 and the accumulator 7. During a heatingoperation, the refrigerant circulates in the refrigerant circuit 6 asdescribed above.

(5) Features

(5-1)

Generally, the heat transfer rate of indoor fins of an indoor heatexchanger can be increased as the interval at which indoor flat tubesare disposed is decreased. Decreasing the interval at which the indoorflat tubes are disposed, however, increases the flow rate of airflowthat passes between the indoor flat tubes and causes dew condensationwater to easily disperse. When the height of each indoor flat tube inthe up-down direction is large, the flow rate of the airflow that passesbetween the indoor flat tubes is similarly increased and causes dewcondensation water to easily disperse. When the interval at which theindoor flat tubes are disposed is increased, the heat transfer rate ofthe indoor fins decreases. Consequently, the evaporation temperature ofthe refrigerant in the indoor heat exchanger is required to bedecreased, which generates environment in which dew condensation wateris easily generated.

In contrast, the indoor heat exchanger 51 according to one or moreembodiments and the air conditioning apparatus 1 that includes theindoor heat exchanger 51 employ the indoor heat exchanger and the airconditioning apparatus that satisfy the relation of 4.0≤DP/HT≤10.0 whereHT represents the height of each indoor flat tube 55 in the up-downdirection and DP represents the pitch of the plurality of indoor flattubes 55 in the up-down direction. It is revealed from analysis data inwhich the values of DP and HT are varied that thus the value of DP/HT ofthe indoor heat exchanger 51 may be set to be in the numerical range forsuppression of dew condensation water.

In other words, thus setting the value of DP/HT of the indoor heatexchanger 51 to 4.0 or more suppresses the flow rate of the airflow thatflows to cross the indoor fins 60 from being increased excessively.Consequently, even when the indoor fan 52 is used with the air volumethereof increased, it is possible to suppress dew condensation waterfrom dispersing from the leeward-side end due to the airflow beinglarge.

Moreover, setting the value of DP/HT of the indoor heat exchanger 51 to10.0 or less causes, of the region in the indoor fins 60, a region faraway from the indoor flat tubes 55 to be small and can improve the heattransfer rate of the indoor fins 60. Therefore, the need to decrease theevaporation temperature of the refrigerant of the indoor heat exchanger51 to ensure the capacity thereof is suppressed. Thus, by causing dewcondensation water not to be generated easily, it is enabled to suppressdispersion of dew condensation water from the indoor fins 60, even whenthe indoor fan 52 is used with the air volume thereof increased.

When the indoor heat exchanger 51 is configured to satisfy the relationof 4.6≤DP/HT≤8.0, it is enabled to make the effect of suppressing thedispersion of dew condensation water more remarkable.

(5-2)

Generally, in an outdoor heat exchanger used in an outdoor unit of anair conditioning apparatus, air flow resistance is easily increased byfrost formation on outdoor fins when the outdoor heat exchangerfunctions as an evaporator for refrigerant. Thus, the pitch of outdoorflat tubes is required to be wide. If a heat exchanger having astructure identical to the structure of such an outdoor heat exchangerthat has a structure in which the pitch of flat tubes is wide is appliedto an indoor heat exchanger, the heat transfer rate of indoor finsdecreases due to the wide pitch of the flat tubes, which requires adecrease in the evaporation temperature of refrigerant in the indoorheat exchanger and causes dew condensation water to be easily generated.

In contrast, the indoor heat exchanger 51 according to one or moreembodiments and the air conditioning apparatus 1 that includes theindoor heat exchanger 51 satisfy a relation in which the value of DP/HTof the indoor heat exchanger 51 is smaller than the value of DP/HT ofthe outdoor heat exchanger 11 where HT represents the height of each ofthe flat tubes 90 and 55 in the up-down direction and DP represents thepitch of the plurality of flat tubes 90 and 55 in the up-down direction.

Therefore, the heat transfer rate of the indoor fins 60 is improved inthe indoor heat exchanger 51, in which dispersion of dew condensationwater easily occurs, while frost formation on the outdoor heat exchanger11, in which dispersion of dew condensation water does not easily occur,when the outdoor heat exchanger 11 is used as the evaporator issuppressed, thereby suppressing the need to decrease the evaporationtemperature of the refrigerant of the indoor heat exchanger 51 when theindoor heat exchanger 51 is used as the evaporator and causing dewcondensation water not to be easily generated. Consequently, it isenabled to suppress dispersion of dew condensation water.

(5-3)

The indoor heat exchanger 51 according to one or more embodimentsincludes the windward heat exchanging section 70 and the leeward heatexchanging section 80 and employs a structure in which at least two rowsor more of the indoor flat tubes 55 are disposed.

Consequently, of the dew condensation water that is generated on theindoor heat exchanger 51, dew condensation water that has been generatedon the windward heat exchanging section 70 is easily guided to movedownward on a portion between the windward heat exchanging section 70and the leeward heat exchanging section 80 or on the leeward heatexchanging section 80 and is to be drained. In addition, air whose drydegree is increased by generating dew condensation water on the windwardheat exchanging section 70 when passing through the windward heatexchanging section 70 is supplied to the leeward heat exchanging section80. It is thus possible to cause the volume of the dew condensationwater that is generated on the leeward heat exchanging section 80 to besmall and to suppress dispersion of dew condensation water from theleeward-side end of the leeward heat exchanging section 80.

(5-4)

In the indoor heat exchanger 51 according to one or more embodiments,the indoor fins 60 each include the indoor continuous portion 64 on theleeward side of the indoor flat tubes 55. Thus, dew condensation waterthat has been generated on the indoor flat tubes 55 is easily drained bybeing guided to move downward on the indoor continuous portions 64 ofthe indoor fins 60 positioned along the downstream side in the airflowdirection. Consequently, it is enabled to suppress dispersion of dewcondensation water from the downstream-side ends of the indoor fins 60in the airflow direction.

In particular, in the indoor heat exchanger 51 according to one or moreembodiments, the structure in which the two rows or more of the indoorflat tubes 55 are disposed includes the indoor continuous portions 64 onthe downstream side of the indoor fins 60 of the leeward heat exchangingsection 80. It is thus enabled to increase drainage of generated dewcondensation water while suppressing generation of dew condensationwater on the downstream-side ends of the indoor fins 60.

(5-5)

The indoor heat exchanger 51 according to one or more embodimentssatisfies the relation of 0.2≤WL/WF≤0.5 where WF represents the lengthof each indoor fin 60 in the airflow direction and WL represents thelength of each indoor continuous portion 64 in the airflow direction. Bythus setting the value of WL/WF to 0.2 or more in the indoor fins 60,the width of each indoor continuous portion 64 in the airflow directionis sufficiently ensured, and the dew condensation water that has beengenerated on the indoor heat exchanger 51 is caused to be easily draineddownward through the indoor continuous portions 64. In addition, bysetting the value of WL/WF to 0.5 or less in the indoor fins 60, of theregion in the indoor fins 60, a region that is far away from the indoorflat tubes 55 and that does not easily contribute to the improvement ofthe heat transfer performance is caused to be small, and it is therebyenabled to suppress material costs while maintaining the performance ofthe indoor fins 60.

In particular, by setting the value of WL/WF of the indoor fins 60 to0.2 or more while positioning the indoor continuous portions 64 of theindoor fins 60 on the downstream side in the airflow direction of theindoor flat tubes 55, it is enabled to increase drainage of the dewcondensation water that has been generated on the indoor flat tubes 55through the indoor continuous portions 64.

(5-6)

The indoor heat exchanger 51 according to one or more embodiments have,in each indoor fin 60, the main slits 62 and the continuous-locationslits 63 that are cut and raised to open in the airflow direction.Consequently, the air supplied to the indoor heat exchanger 51 isenabled to come into contact with the indoor fins 60 sufficiently. It isthus enabled to fully utilize an air heat source.

The upper ends of the main slits 62 and the continuous-location slits 63are disposed to be positioned close to the lower parts of the indoorflat tubes 55 that are positioned directly above. The dew condensationwater that has been generated on the indoor flat tubes 55 positioneddirectly above is thus easily caught and guided to move downward, whichenables an enhancement of drainage. In particular, by designing asillustrated in FIG. 12 such that the distance DS between the portionwhere raising of the fin collar portions 65 a with respect to the majorsurfaces 61 of the indoor fins 60 starts and the portion where raisingof the main slits 62 of the indoor fins 60 starts on the side of thelower-side flat surfaces 55 b of the indoor flat tubes 55 is 1 mm orless, it is possible to suppress the dew condensation water fromremaining on the side of the lower-side flat surfaces 55 b of the indoorflat tubes 55 and to enhance drainage performance.

(6) Modification (6-1) Modification A

The aforementioned embodiments have been described by presenting anexample in which the downstream-side end of each indoor fin 60 has aflat shape.

The shape of the downstream-side end of each indoor fin 60 is, however,not limited thereto. For example, the indoor fins 60 a that each includea water-guiding rib 99 extending along the downstream-side end in theairflow direction, as described below, may be used.

In FIG. 13, the positional relation between the indoor fins 60 a and theindoor flat tubes 55 is illustrated. In FIG. 14, the water-guiding rib99 along, of the B-B section of FIG. 13, a portion in the vicinity ofthe downstream side in the airflow direction is illustrated.

As with the aforementioned embodiments, the indoor heat exchanger 51according to the modification A also includes the windward heatexchanging section 70 and the leeward heat exchanging section 80. Eachof the indoor fins 60 a of the windward heat exchanging section 70 andthe leeward heat exchanging section 80 has the water-guiding rib 99extending vertically along the downstream-side end in the airflowdirection of the indoor continuous portion 64 disposed on the downstreamside in the airflow direction. As illustrated in FIG. 14, thewater-guiding rib 99 is formed to be recessed in the plate thicknessdirection of each indoor fin 60 a with respect to the major surface 61around the water-guiding rib 99. Each water-guiding rib 99 may berecessed more than the plate thickness of each indoor fin 60 a but notlimited thereto.

Thus disposing the water-guiding ribs 99 in the indoor fins 60 a causesthe dew condensation water that has been generated on the indoor heatexchanger 51 to be caught in the water-guiding ribs 99 and causes thedew condensation water to be easily guided to move downward along thewater-guiding ribs 99. Consequently, the dew condensation water issuppressed from reaching the leeward-side ends of the indoor fins 60 a,which enables dispersion of the dew condensation water to besufficiently suppressed.

Each water-guiding rib 99 may be disposed, on the indoor continuousportion 64 of each indoor fin 60 a, on the downstream side from thecenter of the width in the airflow direction. Each water-guiding rib 99may be disposed in a location having a width within, of the width of theindoor continuous portion 64 in the airflow direction, 20% from thedownstream-side end in the airflow direction.

In the indoor fins 60 a on each of which the water-guiding rib 99 isdisposed, in particular, the relation between the width WL of the indoorcontinuous portion 64 of each indoor fin 60 in the airflow direction andthe width WF of each indoor fin 60 in the airflow direction may satisfythe relation of 0.2≤WL/WF.

(6-2) Modification B

The aforementioned embodiments have been described by presenting anexample in which the indoor heat exchanger 51 includes the windward heatexchanging section 70 and the leeward heat exchanging section 80 and inwhich the indoor flat tubes 55 are juxtaposed in two rows.

The number of the rows along which the indoor flat tubes 55 included inthe indoor heat exchanger 51 are disposed side by side in the airflowdirection is, however, not limited to two. The rows may be a pluralityof rows of three or more. Thus increasing the number of the rows of theindoor flat tubes 55 enables dispersion of the dew condensation waterfrom the downstream-side end of the indoor heat exchanger 51 in theairflow direction to be more effectively suppressed.

(6-3) Modification C

The aforementioned embodiments have been described by presenting anexample in which, in the indoor heat exchanger 51, the plurality ofindoor flat tubes 55 belonging to the windward heat exchanging section70 and the plurality of indoor flat tubes 55 belonging to the leewardheat exchanging section 80 are disposed to be superposed on each otherwhen viewed in the airflow direction.

The indoor heat exchanger 51 is, however, not limited thereto. Theplurality of indoor flat tubes 55 belonging to the heat exchangingsection on the further windward side and the plurality of indoor flattubes 55 belonging to the heat exchanging section on the further leewardside may be disposed not to be superposed on each other when viewed inthe airflow direction. Consequently, both the indoor flat tubes 55positioned on the windward side and the indoor flat tubes 55 positionedon the leeward side are enabled to be subjected to sufficient airflow.

(6-4) Modification D

The aforementioned embodiments have been described by presenting anexample in which the indoor fins 60 of the indoor heat exchanger 51include the main slits 62 and the continuous-location slits 63 that areconfigured by being cut and raised such that the entirety of slit piecesis positioned on one side in the plate thickness direction with respectto the major surfaces 61 of the indoor fins 60.

The cut-and-raised portions formed in the indoor fins 60 are, however,not limited thereto. Instead of the main slits 62 and thecontinuous-location slits 63, for example, the cut and raised slitpieces may employ a structure, called louver, in which the windward-sideends of the slit pieces in the airflow direction are positioned on oneside of the major surfaces 61 of the indoor fins 60 in the platethickness direction and in which the leeward-side ends of the slitpieces in the airflow direction are positioned on the other side of themajor surfaces 61 of the indoor fins 60 in the plate thicknessdirection.

Although the disclosure has been described with respect to only alimited number of embodiments, those skilled in the art, having benefitof this disclosure, will appreciate that various other embodiments maybe devised without departing from the scope of the present invention.Accordingly, the scope of the invention should be limited only by theattached claims.

REFERENCE SIGNS LIST

-   -   1 air conditioning apparatus    -   2 outdoor unit (outdoor unit)    -   3 indoor unit (indoor unit)    -   11 outdoor heat exchanger    -   51 indoor heat exchanger    -   55 indoor flat tube (flat tube)    -   55 c flow channel    -   60 indoor fin (heat transfer fin)    -   62 main slit (cut-and-raised portion)    -   63 continuous-location slit (cut-and-raised portion)    -   64 indoor continuous portion (continuous portion)    -   65 windward portion (each portion positioned between the flat        tubes vertically juxtaposed)    -   90 outdoor flat tube (flat tube)    -   90 c flow channel    -   91 outdoor fin (heat transfer fin)    -   97 a continuous portion    -   97 b leeward portion

PATENT LITERATURE

-   PTL 1: Japanese Unexamined Patent Application Publication No.    2016-041986

1.-8. (canceled)
 9. An indoor heat exchanger in an indoor unit of an airconditioning apparatus, the indoor heat exchanger comprising: flat tubesthat are juxtaposed in a vertical direction and that each comprise aflow channel that allows refrigerant to pass through an inner portionthereof, and heat transfer fins joined to the flat tubes and that eachcomprise: a continuous portion that extends continuously in the verticaldirection; and windward portions that are continuous with the continuousportion and are disposed between the flat tubes, wherein 4.0≤DP/HT≤10.0is satisfied, where HT is a height of each of the flat tubes and DP is apitch of the flat tubes.
 10. An indoor heat exchanger in an indoor unitconstituting an air conditioning apparatus together with an outdoor unitthat comprises an outdoor heat exchanger, wherein the outdoor heatexchanger and the indoor heat exchanger each comprise: flat tubes thatare juxtaposed in a vertical direction and that each comprise a flowchannel that allows refrigerant to pass through an inner portionthereof; and heat transfer fins joined to the flat tubes and that eachcomprise: a continuous portion that extends continuously in the verticaldirection; and windward portions that are continuous with the continuousportion and are disposed between the flat tubes, wherein a value ofDP/HT of the indoor heat exchanger is smaller than a value of DP/HT ofthe outdoor heat exchanger, where HT is a height of each of the flattubes and DP is a pitch of the flat tubes.
 11. The indoor heat exchangeraccording to claim 9, wherein the flat tubes each comprise:upstream-side flat tubes on an upstream side in an airflow direction,and downstream-side flat tubes on a downstream side of the upstream-sideflat tubes in the airflow direction.
 12. The indoor heat exchangeraccording to claim 9, wherein the continuous portion is disposed on aleeward side of the flat tubes in an airflow direction.
 13. The indoorheat exchanger according to claim 9, wherein 0.2≤WL/WF≤0.5 is satisfied,where WF is a length of each of the heat transfer fins in an airflowdirection and WL is a length of the continuous portion in the airflowdirection.
 14. The indoor heat exchanger according to claim 9, whereinthe heat transfer fins each comprise a cut-and-raised portion, and alongitudinal direction of the cut-and-raised portion is the verticaldirection.
 15. The indoor heat exchanger according to claim 9, wherein4.6≤DP/HT≤8.0 is satisfied.
 16. An air conditioning apparatuscomprising: an indoor unit comprising the indoor heat exchangeraccording to claim 9, and an outdoor unit comprising an outdoor heatexchanger.